1. Technical Field
Embodiments relate to a thin film transistor and a method of manufacturing the same.
2. Description of the Related Art
A thin film transistor (TFT) is a field effect transistor which may be manufactured on a substrate using a semiconductor thin film. TFTs have widely been used as, e.g., a drive device, a switching device, etc., to operate a pixel in a flat panel display, e.g., an organic light emitting display (OLED) or a liquid crystal display (LCD).
An electronic circuit board that is impact resistant and bendable or foldable has attracted attention as desirable element in electronic devices. The development of an organic TFT, which also has these properties, is desired.
An oxide TFT having improved panel lifetime and high resolution may be desirable because it may exhibit voltage uniformity, which is an advantage of amorphous silicon (a-Si). An oxide TFT may also exhibit high electron mobility, which is an advantage of low temperature polysilicon (LTPS).
In particular, the production of a TFT OLED panel using oxide may deposit the thin film at a relatively low temperature by, e.g., sputtering, without a need for a high-temperature deposition process. This may be simpler than oxidation of existing silicon. Thus, since the production of a TFT OLED panel may lower the manufacturing costs, it has been spotlighted as next generation technology.
However, since an optimal procedure for processing an oxide semiconductor has not yet been completely developed, there still remain problems, e.g., non-uniform dispersion and degradation of characteristics, e.g., electron mobility, of the TFT.
In an oxide TFT, the oxide semiconductor material may be sensitive to, e.g., radiation, ion bombardment from plasma, etc., which may occur in a dry etching process and a film forming process, e.g., chemical vapor deposition (CVD), physical vapor deposition (PVD), etc. Therefore, the characteristics of the oxide TFT device may be degraded, and also the dispersion of the TFT device on a TFT array substrate may be non-uniform.
The dry etching process and the film forming process described above may be used in a process forming an etch stop layer, a contact hole, and source and drain electrodes in a TFT manufacturing technique. The TFT may have a top gate structure or a bottom gate structure. A need exists for the development of material and process which has no adverse effects on the active layers during each process.